Answer:
The characteristics flame test color of metals ions are due to atomic emission spectra.Explanation:
When an atom absorb a specific wavelength radiation, the electron inside in it, move from lower energy level to higher energy level. Such a process is known as absorption. When this excited electron come back to its ground state, it loses energy in specific color depending upon the frequency of absorbed radiation. Such a process is known as emission .Energy level:
As an atom has different energy level, the level near to nucleus has less energy as compare to level that are far from nucleus. So electrons move from lower energy level to higher level by gaining specific energy, and after excitation it come back from high energy level to low energy level with emission of light.Planck's Concept
There is specific energy difference between two energy level, so such energy difference is quantized. only those radiation will be absorbed that are equal to the energy difference between two level.The colors of the flame arise due to absorption or emission spectra. Temperature, electronic spectra, energy difference are some of the factors responsible for flame test colors.
Further explanation:
Flame test is an analytical technique that is used to detect the presence of specific elements on the basis of their corresponding spectrum. The flame colors are dependent on temperature.
Factors responsible for flame test colors:
1. Oxygen supply
In the case of hydrocarbon flames, it is the most important factor in determining the color of the flame. It determines the rate of combustion, temperature and reaction paths, thereby forming different colors.
2. Energy difference
Flame colors are related to the energy difference between the two energy levels of a particular atom. Different atoms have different allowed energy levels for their electrons and therefore producing different flame colors.
3. Temperature
It plays a major role in flame colors. For example, the inner core of candle flame appears blue with a temperature around 1670 K. The color inside the flame ranges from yellow, orange to red. More the distance from the center of the candle flame, lower will be the temperature and vice-versa.
4. Electronic spectra
Each element has its own characteristic electronic spectra that are responsible for producing different flame colors for different elements.
Electronic transition:
It is a process that occurs when an electron undergoes emission or absorption from one energy level to another energy level.
When an electron undergoes a transition from a lower energy level to a higher energy level then it requires energy to complete the process. This transition is an absorption process.
When an electron undergoes a transition from higher energy level to lower energy level then it emits energy to complete the process. This transition is an emission process.
The ground state of an atom is the lowest energy state whereas the excited state has energy greater than that of the ground state.
When light is made to fall on any substance, electrons are emitted from it. This is known as the photoelectric effect and the emitted electrons are called photoelectrons. The electrons are emitted because of the transference of energy from light to the electrons.
According to Planck’s law, energy is proportional to the frequency and is expressed as follows:
[tex]{\text{E}}{\mathbf{ = }}{h\nu }}[/tex] …… (1)
Here,
[tex]E[/tex]is the energy.
[tex]h[/tex]is the Plank’s constant.
[tex]\nu[/tex]is the frequency.
According to equation (1), only radiations with particular frequencies can be transmitted by an atom, thereby resulting in absorption or emission of light.
As long as an electron remains in the same energy level, it neither absorbs nor emits energy. But energy is absorbed when an electron goes from lower to higher energy level and it is emitted when an electron jumps from higher to lower energy levels.
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Answer details:
Grade: Senior School
Subject: Chemistry
Chapter: Atomic structure
Keywords: electronic transition, absorption, emission, lower, higher, energy level, excited state, ground state, emit, lower energy state, flame test, temperature, spectra, oxygen supply.
Calcium has an atomic mass of 40 and an atomic number of 20, so the number of neutrons must be _______________
The atom would have 20 neutrons.
Mass number = neutrons + protons
40 = neutrons + 20
neutrons = 40 – 20 = 20
Suppose you find a rock originally made of potassium-40, half of which decays into argon-40 every 1.25 billion years. You open the rock and find 31 atoms of argon-40 for every atom of potassium-40. How long ago did the rock form?
We see that in 1 rock, there are 31 atoms of Argon and 1 atom of Potassium so the relative concentration of Potassium is:
1 / 32
or can be written as:
1 / 2^5
So this means that 5 half-lives have passed.
So the years are:
years passed = 5 * 1.25 billion years = 6.25 billion years
Answer:
1.3 billion years
Explanation:
Evaporation is ________. check all that apply. check all that apply. an endothermic process sometimes a warming process always a cooling process sometimes a cooling process an exothermic process always a warming process
Evaporation is an endothermic process that requires the absorption of heat to occur, typically resulting in a perceived cooling effect. However, it is not inherently a cooling or warming process, nor is it an exothermic process.
Explanation:Evaporation is an endothermic process, meaning it requires an input of heat to occur. The heat energy is used to overcome intermolecular attractions, allowing matter to change from one physical state to another. This is why when you leave a swimming pool or when you sweat, you feel cool. The process of evaporation absorbs heat from your body.
However, it's important to note that evaporation is not always a cooling process. While evaporation takes heat from the source, it doesn't inherently reduce the temperature of the source, the perceived cooling is due to the loss of heat. Also, evaporation is not a warming process, or an exothermic process, as it doesn't produce heat. In fact, the reverse process of evaporation - condensation - is exothermic, releasing heat as matter changes state.
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Write a chemical equation representing the first ionization energy for lithium. use e− as the symbol for an electron.
The first ionization energy for lithium has been represented as:
[tex]\rm \bold{Li\;\rightarrow\;Li^+\;+\;e^-}[/tex]
Ionization energy can be described as the smallest amount of energy necessary to remove the most loosely attached electron from an isolated neutral gaseous atom.
The first ionization energy has been the amount of energy needed to remove the first electron from an atom's outermost energy level.
The second ionization energy is the amount of energy required to remove the second electron and produce a divalent cation.
Thus, for lithium, initial ionization energy is represented by the chemical equation;
[tex]\rm \bold{Li\;\rightarrow\;Li^+\;+\;e^-}[/tex]
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The first ionization energy for lithium (Li) is represented by the chemical equation Li(g) → Li+(g) + e−, and requires an energy of approximately +54.4 eV.
Explanation:The first Ionization energy refers to the amount of energy required to remove an electron from a gaseous atom or ion. For lithium, which is an alkali metal with atomic number 3, the electron configuration is [He]2s¹. In the case of Lithium, the first ionization energy removes the outermost electron, resulting in a Lithium-ion (Li+) and an electron (e−). This is represented by the chemical equation: Li(g) → Li+(g) + e−. This process requires a particular amount of energy.
The energy required to ionize the electron of Lithium is approximately +54.4 eV (electron Volts).
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Name the product formed by the reduction of d-gulose.
Final answer:
Reduction of D-gulose typically produces D-gulitol (sorbose alcohol), a sugar alcohol. This reaction is analogous to the reduction of D-glucose to sorbitol, involving conversion of the aldehyde group to an alcohol.
Explanation:
The student asked about the product formed by the reduction of D-gulose. D-Gulose, an aldose sugar, can undergo reduction to yield a sugar alcohol, similar to how D-glucose can be reduced to sorbitol. In the case of D-gulose, the reduction typically would produce D-gulitol, also known as sorbose alcohol.
The reducing sugar characteristic mentioned in reference to lactose is due to the presence of a free aldehyde group or an equivalent group in cyclic forms that can act as a reducing agent, for instance in Fehling's solution or Tollen's reagent reactions. This is relevant because the reduction of D-gulose would involve the conversion of its aldehyde group to an alcohol.
Why does carbon acculate quicker in boreal peatlands?
Zn(s)+cu2+(aq)→zn2+(aq)+cu(s). part a under standard conditions, what is the maximum electrical work, in joules, that the cell can accomplish if 51.0 g of copper is plated out?
the maximum electrical work that the cell can accomplish when 51.0 g of copper is plated out is approximately [tex]\( -167549 \, \text{J} \).[/tex]
To find the maximum electrical work that the cell can accomplish when 51.0 g of copper is plated out, we can use the relationship between electrical work ( w ) and the amount of substance involved in the redox reaction.
The electrical work ( w ) done by a cell operating under standard conditions is given by:
[tex]\[ w = -nFE \][/tex]
Where:
- ( n ) is the number of moles of electrons transferred in the balanced redox reaction.
- ( F ) is the Faraday constant [tex](\( 96485 \, \text{C/mol} \)).[/tex]
- ( E ) is the standard cell potential of the redox reaction (in volts).
First, we need to determine the number of moles of electrons transferred in the reaction. From the balanced redox reaction:
[tex]\[ \text{Zn}(s) + \text{Cu}^{2+}(aq) \rightarrow \text{Zn}^{2+}(aq) + \text{Cu}(s) \][/tex]
We see that 2 moles of electrons are transferred for every 1 mole of copper plated out.
Given that the molar mass of copper ([tex]\( \text{Cu} \))[/tex] is approximately [tex]\( 63.55 \, \text{g/mol} \)[/tex], we can calculate the number of moles of copper plated out:
[tex]\[ \text{Moles of Cu} = \frac{\text{Mass}}{\text{Molar mass}} = \frac{51.0 \, \text{g}}{63.55 \, \text{g/mol}} \][/tex]
[tex]\[ \text{Moles of Cu} \approx 0.802 \, \text{mol} \][/tex]
Since 2 moles of electrons are transferred for every 1 mole of copper plated out, the number of moles of electrons transferred (\( n \)) is twice the number of moles of copper plated out:
[tex]\[ n = 2 \times 0.802 \, \text{mol} \][/tex]
[tex]\[ n = 1.604 \, \text{mol} \][/tex]
Now, we can use the standard reduction potentials to find the standard cell potential (E ) for the reaction. From the standard reduction potentials table, we have:
[tex]\[ E^\circ_{\text{cell}} = E^\circ_{\text{cathode}} - E^\circ_{\text{anode}} \][/tex]
[tex]\[ E^\circ_{\text{cell}} = E^\circ_{\text{Cu}^{2+}/\text{Cu}} - E^\circ_{\text{Zn}^{2+}/\text{Zn}} \][/tex]
Given that [tex]\( E^\circ_{\text{Cu}^{2+}/\text{Cu}} = 0.34 \, \text{V} \) and \( E^\circ_{\text{Zn}^{2+}/\text{Zn}} = -0.76 \, \text{V} \)[/tex], we have:
[tex]\[ E^\circ_{\text{cell}} = (0.34 \, \text{V}) - (-0.76 \, \text{V}) \][/tex]
[tex]\[ E^\circ_{\text{cell}} = 1.10 \, \text{V} \][/tex]
Now, we can calculate the maximum electrical work [tex](\( w \)):[/tex]
[tex]\[ w = -nFE \][/tex]
[tex]\[ w = -(1.604 \, \text{mol} \times 96485 \, \text{C/mol} \times 1.10 \, \text{V}) \][/tex]
[tex]\[ w \approx -1.604 \times 96485 \times 1.10 \, \text{J} \][/tex]
[tex]\[ w \approx -167548.6 \, \text{J} \][/tex]
[tex]\[ w \approx -167549 \, \text{J} \][/tex]
So, the maximum electrical work that the cell can accomplish when 51.0 g of copper is plated out is approximately [tex]\( -167549 \, \text{J} \).[/tex]
A sample of 0.010 mole of oxygen gas is confined at 127 °c and 0.80 atmosphere. what would be the pressure of this sample at 27 °c and the same volume?
To find the pressure of the sample at 27 °C and the same volume, you can use the combined gas law equation. Plugging in the given values and solving for the unknown pressure, you will find that it is 0.71 atm.
Explanation:To solve this problem, we can use the combined gas law:
P1*V1/T1 = P2*V2/T2
Where P1, V1, and T1 are the initial pressure, volume, and temperature, and P2, V2, and T2 are the final pressure, volume, and temperature.
Given that the initial volume is the same as the final volume, we can set V1 = V2:
P1/T1 = P2/T2
Plugging in the values, we have (0.80 atm)/(127 + 273) K = P2/(27 + 273) K
Solving for P2, we get:
P2 = (0.80 atm)(300 K)/(300 + 27) K = 0.71 atm
Therefore, the pressure of the sample at 27 °C and the same volume would be 0.71 atm.
Compare the small egg and the jumbo egg drop results when all other conditions were unchanged. What affect does doubling the mass of an egg have upon the force that the egg experiences?
Doubling the mass of an egg results in doubling the force it experiences upon impact in an egg drop experiment due to Newton's Second Law (F = ma). This principle holds true if all other conditions remain the same, such as the height of the drop and the surface properties.
When performing an egg drop experiment with a small egg and a jumbo egg under identical conditions, the force experienced by the egg can be analyzed using Newton's Second Law of Motion, which states that force equals mass times acceleration (F = ma).
Doubling the mass of the egg will result in doubling the force experienced by the egg during impact, assuming the acceleration due to gravity remains constant. This principle can be observed in scenarios like dropping two balls of different masses but the same volume, where the heavier ball experiences more force upon impact.
If you throw eggs at a bed sheet, the eggs likely won't break because the bed sheet increases the time over which the force is applied, thus reducing the impact force.
In summary, doubling the mass of an egg will double the force it experiences during the drop, provided all other conditions, such as the height from which it is dropped and the properties of the impact surface, remain unchanged.
Secondary colors can be created from a mixture of __________
Secondary colors can be created from a mixture of primary colors, namely red, blue, and yellow. This is part of the subtractive color process. In the additive color process that involves light, the primary colors are red, green, and blue.
Explanation:Secondary colors can be created from a mixture of primary colors, which are red, blue, and yellow. When these primary colors are mixed in the right proportions, they can produce secondary colors. For example, mixing red and blue in equal proportions results in purple, a secondary color. Similarly, a mixture of blue and yellow generates green, while red and yellow produce orange. These are examples of the subtractive color process, often associated with pigment mixing.
The human eye perceives a mixture of all colors in sunlight as white light. This fact is related to the additive color process, primarily concerned with light. Specifically, in this process, red, green, and blue are treated as primary colors. Their combinations can yield secondary colors, and when combined at full intensity, they give white light.
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What is the energy associated with an object’s motion called
Name the two properties of elections that indicate a wave-like nature.
Which of the reactions below is a formation reaction? 1. 2 fe(s) + 3 o(g) → fe2o3(s) 2. n2(g) + 2 h2(g) + 1 2 o2(g) → n2h4o(g) 3. b2(s) + 2 i2(ℓ) + cl2(g) → 2 bi2cl(g) 4. cdiamond(s) + 1 2 o2(g) → co(g)?
Reaction (1) is a formation reaction because it represents the formation of Fe2O3(s) from its constituent elements Fe(s) and O2(g) in their standard states.
What is a formation reaction?A formation reaction is a chemical reaction in which one mole of a compound is formed from its constituent elements in their standard state under standard conditions of temperature and pressure (STP). The standard state of an element is its most stable physical state at STP.
In a formation reaction, the reactants are always the elements from which the compound is formed, and the product is always the compound itself. The enthalpy change of a formation reaction is known as the standard enthalpy of formation (ΔHf°) and is a measure of the heat absorbed or released during the formation of one mole of the compound.
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Final answer:
The given reaction forming iron (III) oxide from iron and oxygen is identified as a formation reaction, adhering to the definition by involving elemental components in their standard states.
Explanation:
The question asks which of the given reactions is a formation reaction. A formation reaction is one in which a single compound is formed from its constituent elements in their standard states.
From the provided options, the first reaction, 2 Fe(s) + 3 O2(g) → Fe2O3(s), is a formation reaction because iron (III) oxide, Fe2O3, is being formed from its elemental components (iron and oxygen) in their standard states (solid for iron and gas for oxygen).
The change of state from solid to gas without an intermediate liquid state is called evaporation. true and false
The isotope 3115p is also called ___________
phosphorus-46
phosphorus-31
phosphorus-16
phosphorus-15
how much would the boiling point of water increase if 4 mol of suagr were added to 1kg of water
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What is the velocity of an car that travels 50 miles north, turns around and travels 50 miles south, in 5 hours?
Question 6 options:
5 mph south
2 mph south
0
25 mph north
How many molecules of hypothetical substance b are produced when 29.9g of hypothetical substance a reacts? the molar mass of substance a is 15.7 g/mol?
1. **Convert the mass of A to moles:**
- [tex]\(29.5 \, \text{g}\)[/tex] of A is approximately [tex]\(1.88 \, \text{mol}\)[/tex].
2. **Convert the number of moles of A to the number of moles of B:**
- [tex]\(1.88 \, \text{mol}\)[/tex] of A corresponds to approximately [tex]\(2.82 \, \text{mol}\)[/tex] of B.
3. **Convert the number of moles of B to the molecules of B:**
- [tex]\(2.82 \, \text{mol}\)[/tex] of B is approximately [tex]\(1.70 \times 10^{24}\)[/tex] molecules.
**Convert the mass of A to moles:**
The first step is to convert the mass of substance A to moles using its molar mass. The formula for moles [tex](\(n\))[/tex] is given by the mass [tex](\(m\))[/tex] divided by the molar mass [tex](\(M\)):[/tex]
[tex]\[ n_A = \frac{m_A}{M_A} \][/tex]
Given that the mass of substance A [tex](\(m_A\))[/tex] is 29.5 g and its molar mass [tex](\(M_A\))[/tex] is 15.7 g/mol:
[tex]\[ n_A = \frac{29.5 \, \text{g}}{15.7 \, \text{g/mol}} \approx 1.88 \, \text{mol} \][/tex]
**Convert the number of moles of A to the number of moles of B:**
The reaction ratio states that 2 moles of A produce 3 moles of B. Therefore, if [tex]\(n_A\)[/tex] is 1.88 mol, the corresponding moles of B [tex](\(n_B\))[/tex] can be calculated using the ratio:
[tex]\[ n_B = \frac{3}{2} \times n_A \][/tex]
[tex]\[ n_B = \frac{3}{2} \times 1.88 \, \text{mol} \approx 2.82 \, \text{mol} \][/tex]
**Convert the number of moles of B to the molecules of B:**
To convert moles of B to molecules [tex](\(N_B\))[/tex], you use Avogadro's number [tex](\(6.022 \times 10^{23}\) mol\(^{-1}\)):[/tex]
[tex]\[ N_B = n_B \times N_A \][/tex]
[tex]\[ N_B = 2.82 \, \text{mol} \times (6.022 \times 10^{23} \, \text{mol}^{-1}) \approx 1.70 \times 10^{24} \, \text{molecules} \][/tex]
The question probable may be:
In a chemical reaction, exactly 2 mol of substance A react to produce exactly 3 mol of substance B.
How many molecules of substance B are produced when 29.5 g of substance A reacts? The molar mass of substance A is 15.7 g/mol.
Convert the mass of A to moles
Convert the number of moles of A to the number of moles of B
Convert the number of moles of B to the molecules of B
What is the process where a liquid changes from its liquid state to a gaseous state?
Answer:
evaporation
Explanation:
Evaporation is the process where a liquid, in this case water, changes from its liquid state to a gaseous state. Liquid water becomes water vapor. Although lower air pressure helps promote evaporation, temperature is the primary factor.
The enthalpy of formation of liquid ethanol (c2h5oh) is −277.6 kj/mol. what is the equation that represents the formation of liquid ethanol?
The enthalpy of formation of liquid ethanol (C2H5OH) is represented by the chemical equation combining carbon (solid), hydrogen gas, and oxygen gas to form ethanol.
The enthalpy of formation of liquid ethanol (C2H5OH) can be represented by the balanced chemical equation showing its formation from its elements in their standard states.
The equation is as follows:
C(s) + 3H2(g) + 1/2O2(g) → C2H5OH(l)
The enthalpy change for this reaction is -277.6 kJ/mol, indicating that the formation of liquid ethanol from its elements is exothermic.
If the mass of an object increases, the force acting on it, such as gravitational force, also increases.
Answer:
Gravitational force will increase with greater mass
How many moles of al(cn)3 are in 225 g of the compound?
chemistry omg need help plz I need plz. I real badly at it and try to get better but plz help me
How do you know a chemical reaction has occurred in a candle?
Calculate the mass of naoh needed to prepare 100. ml of 0.15m solution.
To prepare 100 mL of a 0.15 M NaOH solution, you will need approximately 0.60 g of NaOH.
Explanation:To calculate the mass of NaOH needed to prepare a 0.15 M solution, we need to use the formula:
Mass (g) = Molarity (M) x Volume (L) x Molar Mass (g/mol)
In this case, the molarity is 0.15 M and the volume is 100 mL (or 0.1 L). The molar mass of NaOH is 22.990 + 15.999 + 1.008 = 39.997 g/mol.
Mass (g) = 0.15 M x 0.1 L x 39.997 g/mol = 0.5999 g, which can be rounded to 0.60 g.
How many moles are in 1.2 x10^3 grams of ammonia, NH3
Synfuels are made from energy sources that are more plentiful than _____.
carbon
oil
sunlight
water
The answer is: oil.
Synfuel (synthetic fuel) is a liquid fuel, rarely gaseous fuel, made from syngas.
Syngas is a mixture of carbon monoxide (CO) and hydrogen (H₂).
Syngas goes to additional conversion process to become liquid fuel.
Some methods for manufacturing synthetic fuels are methanol (CH₃OH) to gasoline conversion and direct coal liquefaction.
Express a time period of exactly 7 day in terms of seconds.
The boiling temperature of water is so much higher than that of methane because water molecules are
You have a 70% solution of dextrose. how many grams of dextrose are in 500 ml of this solution?
Answer:
350g dextrose
Explanation:
To calculate how many g of dextrose are in 500ml of solution we have to know the following:
When we talk about x% m/v (mass / volume) it means that there are x grams of solute in 100 ml of solution. Then 70% means that there is 70g of dextrose per 100ml of solution.
To solve this we can say that if in 100 ml there are 70g. How many grams are in 500 ml?
We apply the simple three rule and solve:
100ml -----------> 70g dextrose
500ml----------> X g dextrose
500ml x 70g / 100ml = X
350g = X
There are 350 grams of dextrose in 500 ml of the 70% dextrose solution.
A 70% solution of dextrose means that the solution contains 70 grams of dextrose per 100 milliliters of solution.
To calculate the grams of dextrose in 500 ml of this solution, we can set up a proportion:
(70 g / 100 ml) = (x g / 500 ml)
To solve for x, we can cross-multiply and then divide:
70 g * 500 ml = 100 ml * x g
35,000 g·ml = 100 ml * x g
Dividing both sides by 100 ml: 350 g = x g
Thus, there are 350 grams of dextrose in 500 ml of the 70% dextrose solution.
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